ADP2300/ADP2301 Step-Down Switching Regulator (Buck Converter)

There are various ways to design Buck Converter and one of them is to used high efficiency buck converter IC. The ADP2300 and ADP2301 are high-efficiency, fixed-frequency step-down (buck converter) regulators with integrated power switches, ideal for compact power supply designs. 

A typical step-down (buck) regulator configuration using the ADP2300 or ADP2301 is shown in the figure below. 

These two devices are functionally similar, with the key difference being their fixed internal switching frequency:

• ADP2300 operates at 700 kHz

• ADP2301 operates at 1.4 MHz

Unlike the ADP1612/ADP1613 boost converters, these devices do not offer pin-selectable frequencies.

The regulators operate using pulse-width modulation (PWM) and offer high efficiency—up to 91%, depending on the load current. As shown in the figure below, the efficiency remains fairly consistent (around 88–91%) once the load current exceeds about 0.2 A. 

In the example shown, the output voltage is held constant at 5 V.

📌 Voltage Range:

• Input Voltage: 3 V to 20 V

• Output Voltage: Adjustable up to 20 V

• The output voltage is typically within 80% to 85% of the input voltage (i.e., $V_{\text{OUT}} \approx 0.8 \times V_{\text{IN}}$ to $0.85 \times V_{\text{IN}}$).

🔒 Built-in Protections:

• Thermal Shutdown Protection (TSP): Activates when the temperature exceeds 140°C and resets when it cools to 150°C.

• Under-voltage Lockout (UVLO): Prevents unstable behavior if input voltage drops too low.

• Short-Circuit Protection: Guards against excessive current draw or output faults.

⚙️ Bootstrap Pin (BST):

One key feature unique to this step-down design is the BST (bootstrap) pin, which is not present in the ADP1612/1613 boost converters.

• A capacitor must be connected between BST (pin 1) and SW (pin 6).

• This capacitor helps drive the internal high-side MOSFET, enabling full switching operation by generating a voltage difference between BST and SW.

This makes the ADP2300/ADP2301 ideal for applications requiring compact, efficient step-down conversion in systems operating from higher voltage sources like 12 V or 19 V power adapters.

Buck Converter can also be designed with microcontrollers. See how to build buck converter with Arduino and how to build buck converter with 555 Timer. If you are interested in boost converter IC then see ADP1612/ADP1612 Step-Up Switching Regulator (Boost Converter).